I disagree that there are bad intentions behind the French policy, or that it's harmful to Vietnamese citizens, I think it's actually helpful to both French and Vietnamese citizens.
The French government decided to take on the cost and responsibility of vaccinating its own citizens in Vietnam. By doing so, it has taken the cost off of the Vietnamese government to vaccinate French citizens in Vietnam. Vietnam would likely praise assistance in vaccinating people living in Vietnam, expats or otherwise. As it stands, it looks like the Vietnamese government will be paying for foreign vaccines in order to vaccinate US expats in Vietnam as well as citizens of other nations. How is that additional burden helpful?
The Vietnamese government made it abundantly clear they were interested in working with foreign governments to vaccinate expats in Vietnam. This makes sense, that Vietnam would like to have as many people living here get vaccinated for as low cost as possible, foreign or not. Governments worldwide, including the Vietnamese government, have taken a policy position that every person vaccinated helps to control pandemic. The Vietnamese government has stated publicly they intend to vaccinate everyone. Vaccinated expats are less likely to carry and spread the virus in their community, and less likely to place additional burden on hospitals.
The topic of favoritism is coming up a lot in these threads. Was it favoritism for governments to vaccinate their overseas diplomats, politicians, and VIPs abroad? How about a diplomat's family, professional athletes, politicians, corporate VIPs, celebrities, and their families? I don't recall seeing much outrage when this happened, nor continued finger pointing at that group of people, when they were placed at the front of the line.
I also saw a post here recently comparing expats getting vaccinated to stealing meals from local citizens. I feel like I'm doing my part in helping the local community if I get vaccinated. I'm in a low risk group, but I don't want to get and transmit covid to the grandmothers and grandfathers nearby, or my wife's parents, or younger people with cancer treatments, etc. I'm sincere about that, I'm not particularly worried about how my body, in my condition, will respond to the virus itself, right or wrong, that's just how I feel about it.
That's from a public policy and moral standpoint. From a personal preservation point of view, I can understand the position of expats, many at higher risk than myself, who've paid the same taxes as citizens in their countries of origin to fund and create these vaccines, and would like the same treatment as their peer citizens regardless of their place of residence. If additional cost is the issue, surely the US government would allow expats so interested to pay even more tax for the shipping and logistics? Yet cost apparently was not too much of an issue for the French government.
Vietnam quickly shut down the argument that the regulations of other nations would make it impossible for foreign nations to vaccinate their own expats in Vietnam, and made it crystal clear Vietnam was interested in facilitating this. I see a government trying to control a pandemic within it's borders, and moves that it makes, such as allowing foreign governments to vaccinate their expats, is one method of many in doing so. Every shot Vietnam has to buy for an expat is also competing for use by a Vietnamese citizen, is that not the case?